Utilization of process heat by-product

ABSTRACT

Heat recovery systems and methods for producing electrical and/or mechanical power from a process heat by-product are provided. Sources of process heat by-product include hot flue gas streams, high temperature reactors, steam generators, gas turbines, diesel generators, and process columns. Heat recovery systems and methods include a process heat by-product stream for directly heating a working fluid of an organic Rankine cycle. The organic Rankine cycle includes a heat exchanger, a turbine-generator system for producing power, a condenser heat exchanger, and a pump for recirculating the working fluid to the heat exchanger.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional PatentApplication No. 61/390,397, entitled “Utilizing Waste Heat From RefineryOperations” and filed on Oct. 6, 2010, in the name of John David Pentonet al, the entire disclosure of which is hereby fully incorporatedherein by reference.

TECHNICAL FIELD

The present application generally relates to heat recovery andutilization. More particularly, the present application relates to theutilization of process heat by-product to generate electricity and/ormechanical power.

BACKGROUND

Objective and regulations surrounding carbon and energy usage has raisedthe importance of designing and retrofitting existing processes forhigher levels of energy efficiency. The primary driving forces are theneed to reduce greenhouse gas emissions or local pollution, reducing theenergy investment requirement, and best utilizing existing supplycapacities to improve the access to energy. To increase the energyefficiency of a process, it is necessary to improve the utilization ofthe energy inputted and reduce the energy wasted to the atmosphere. Onecommon area of wasted energy is in the heat exhausted from sourceswithin the oil and gas industry, from processes such as fluid catalyticcracking regenerator column overheads, steam generator exhaust, turbineexhaust, and other flue gas sources.

Currently, methods for recovering higher temperature waste heat includeutilizing the heat for preheat of other processes or for the productionof steam. This heat can be utilized in heat recovery steam generators orheat exchangers. One such avenue of increasing the energy efficiency ofa process is to utilize the low temperature “waste heat”, typicallybelow 500 degrees Fahrenheit (° F.), for power generation or mechanicalpower. In geothermal applications and reciprocating engines, an organicRankine cycle system is utilized for the conversion of heat to power.The exhaust gas or brine exchanges with a working fluid to produce thedesired power output. However, there are currently several drawbackswith utilization of an organic Rankine cycle in a refining process orvarious flue gas exhaust systems. The current technologies have beenunable to reach the necessary efficiencies at the low temperature rangesof these process streams. Additionally, current technologies have beenunable to incorporate appropriate exchanger technology that wouldsufficiently decrease fouling and reliability risks in a process withvolatile flowrates and temperatures. There are also difficulties withstructurally integrating the technology within a much more complexprocess setting when compared to the current installations.

Therefore, a need exists for a process to effectively and efficientlycapture and convert this waste heat to a useful energy source.

SUMMARY

The present invention is directed to processes for heat recovery fromprocess heat by-product, wherein such heat recovery is realized bychanneling thermal energy from a process heat by-product stream to anorganic Rankine cycle—from which electricity can be derived through aturbine-driven generator. The present invention is also directed tosystems for implementing such processes.

In one aspect of the invention, a process for directly utilizing processheat by-product from refinery operations includes two sub-processes thatoccur simultaneously and that are linked via a heater or heat exchanger.In the first sub-process, a process heat by-product stream is directedto a heater and is utilized to heat a working fluid stream of an organicRankine cycle to produce a cooled by-product stream and a heated workingfluid stream. The cooled by-product stream is then exhausted toatmosphere. In some instances, the process heat by-product streamincludes flue gas from a fluid catalytic cracking unit or recovered heatfrom a high temperature reactor, such as a fired heater, incinerator,hydrotreater, catalytic reformer, or isomerization unit. In the secondsub-process, the working fluid stream is heated by the process heatby-product stream in the heater to form a heated working fluid stream.In certain aspects, the heated working fluid stream is vaporized. Theheated working fluid stream is passed through a turbine-generator set toform an expanded working fluid stream and produce electricity and/ormechanical power. The expanded working fluid stream is then directed toanother heat exchanger to form a condensed working fluid stream. Thecondensed working fluid stream is then passed through a pump to form theworking fluid stream that enters the heater of the organic Rankinecycle.

In another aspect of the invention, a process for directly utilizingwaste heat by-product includes two sub-processes that occursimultaneously and that are linked via a heater or heat exchanger. Inthe first sub-process, a waste heat by-product stream is directed to aheater and is utilized to heat a working fluid stream of an organicRankine cycle to produce a cooled by-product stream and a heated workingfluid stream. The cooled by-product stream is then exhausted toatmosphere. In certain aspects, the cooled by-product stream is directedto an incinerator, a scrubber, or a stack prior to being exhausted tothe atmosphere. In certain aspects, the process heat by-product streamincludes waste heat from a steam generator, gas turbine, or dieselgenerator. In the second sub-process, the working fluid stream is heatedby the waste heat by-product stream in the heater to form a heatedworking fluid stream. In certain aspects, the heated working fluidstream is vaporized. The heated working fluid stream is passed through aturbine-generator set to form an expanded working fluid stream andproduce electricity and/or mechanical power. The expanded working fluidstream is then directed to another heat exchanger to form a condensedworking fluid stream. The condensed working fluid stream is then passedthrough a pump to form the working fluid stream that enters the heaterof the organic Rankine cycle.

In yet another aspect of the invention, a process for directly utilizinga heat by-product stream includes two sub-processes that occursimultaneously and that are linked via a heater or heat exchanger. Inthe first sub-process, a heat by-product stream is directed to a heaterand is utilized to heat a working fluid stream of an organic Rankinecycle to produce a cooled by-product stream and a heated working fluidstream. The cooled by-product stream is then exhausted to atmosphere. Incertain aspects, the cooled by-product stream is directed to anincinerator, a scrubber, or a stack prior to being exhausted to theatmosphere. In the second sub-process, the working fluid stream isheated by the heat by-product stream in the heater to form a heatedworking fluid stream. In certain aspects, the heated working fluidstream is vaporized. The heated working fluid stream is passed through aturbine-generator set to form an expanded working fluid stream andproduce electricity and/or mechanical power. The expanded working fluidstream is then directed to another heat exchanger to form a condensedworking fluid stream.

The features of the present invention will be readily apparent to thoseskilled in the art upon a reading of the description of the preferredembodiments that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the exemplary embodiments of thepresent invention and the advantages thereof, reference is now made tothe following description in conjunction with the accompanying drawings,which are briefly described as follows.

FIG. 1 is a schematic diagram of a heat recovery system for utilizationof waste heat from a fluid catalytic cracking unit, according to anexemplary embodiment.

FIG. 2 is a schematic diagram of a heat recovery system for utilizationof waste heat from a fluid catalytic cracking unit, according to anotherexemplary embodiment.

FIG. 3 is a schematic diagram of a heat recovery system for utilizationof waste heat from a fluid catalytic cracking unit, according to yetanother exemplary embodiment.

FIG. 4 is a schematic diagram of a heat recovery system for utilizationof waste heat from a fluid catalytic cracking unit, according to yetanother exemplary embodiment.

FIG. 5 is a schematic diagram of a heat recovery system for utilizationof process heat by-product from a fired heater unit, according to anexemplary embodiment.

FIG. 6 is a schematic diagram of a heat recovery system for utilizationof process heat by-product from a fired heater unit, according toanother exemplary embodiment.

FIG. 7 is a schematic diagram of a heat recovery system for utilizationof process heat by-product from a fired heater unit, according to yetanother exemplary embodiment.

FIG. 8 is a schematic diagram of a heat recovery system for utilizationof process heat by-product from a fired heater unit, according to yetanother exemplary embodiment.

FIG. 9 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a steam generator unit, according to anexemplary embodiment.

FIG. 10 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a steam generator unit, according toanother exemplary embodiment.

FIG. 11 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a steam generator unit, according to yetanother exemplary embodiment.

FIG. 12 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a steam generator unit, according to yetanother exemplary embodiment.

FIG. 13 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a gas turbine unit, according to anexemplary embodiment.

FIG. 14 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a gas turbine unit, according to anotherexemplary embodiment.

FIG. 15 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a gas turbine unit, according to yetanother exemplary embodiment.

FIG. 16 is a schematic diagram of a heat recovery system for utilizationof an exhaust gas stream from a gas turbine unit, according to yetanother exemplary embodiment.

FIG. 17 is a schematic diagram of a heat recovery system for utilizationof a process heat stream, according to an exemplary embodiment.

FIG. 18 is a schematic diagram of a heat recovery system for utilizationof a process heat stream, according to another exemplary embodiment.

FIG. 19 is a schematic diagram of a heat recovery system for utilizationof a process heat stream, according to yet another exemplary embodiment.

FIG. 20 is a schematic diagram of a heat recovery system for utilizationof a process heat stream, according to yet another exemplary embodiment.

DETAILED DESCRIPTION

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. One of ordinary skill in the art willappreciate that in the development of any such actual embodiment,numerous implementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present invention may be better understood by reading the followingdescription of non-limitative embodiments with reference to the attacheddrawings wherein like parts of each of the figures are identified by thesame reference characters. The words and phrases used herein should beunderstood and interpreted to have a meaning consistent with theunderstanding of those words and phrases by those skilled in therelevant art. No special definition of a term or phrase, for example, adefinition that is different from the ordinary and customary meaning asunderstood by those skilled in the art, is intended to be implied byconsistent usage of the term or phrase herein. To the extent that a termor phrase is intended to have a special meaning, for instance, a meaningother than that understood by skilled artisans, such a specialdefinition will be expressly set forth in the specification in adefinitional manner that directly and unequivocally provides the specialdefinition for the term or phrase. Moreover, various streams orconditions may be referred to with terms such as “hot,” “cold,” “cooled,“warm,” etc., or other like terminology. Those skilled in the art willrecognize that such terms reflect conditions relative to another processstream, not an absolute measurement of any particular temperature.

FIG. 1 shows a direct heat recovery system 100 for utilization of a fluegas stream 102 from a fluid catalytic cracking regenerator unit 101.Generally, the flue gas stream 102 is a high temperature heat streamthat is generated by the combustion of coke in the fluid catalyticcracking regenerator unit 101. In certain embodiments, the flue gasstream 102 has a temperature in the range of from about 1100 to about1800° F. In certain exemplary embodiments, when the combustion of cokeis complete, at least a portion 102 a of the flue gas stream 102 entersa waste heat steam generator 103. A boiler feed water stream 104 alsoenters the waste heat steam generator 103, and heat from the flue gasstream 102 is utilized to heat the boiler feed water stream 104 toproduce a steam stream 105. In certain embodiments, the waste heat steamgenerator 103 generates steam at pressures in the range of from about 15to about 1100 pound-force per square inch gauge (psig). A reduced heatflue gas stream 106 then exits the waste heat steam generator 103 andenters an electrostatic precipitator 107, which removes any catalystfines 108 present in the reduced heat flue gas stream 106 to produce areduced fines flue gas stream 109. In certain exemplary embodiments, thereduced fines flue gas stream 109 has a temperature in the range of fromabout 350 to about 800° F.

In certain embodiments, when the combustion of coke is incomplete andthe flue gas stream 102 contains significant amounts of carbon monoxide,at least a portion 102 b of the flue gas stream 102 enters a carbonmonoxide boiler 110. A fuel stream 111 and an air stream 112 also enterthe boiler 110 to combust the carbon monoxide in the flue gas stream102. A boiler feed water stream 114 also enters the boiler 110, and heatfrom the combustion process and the flue gas stream 102 is utilized toheat the boiler feed water stream 114 to produce a steam stream 115. Incertain embodiments, the boiler 110 operates at a pressure in the rangeof from about 15 to about 1100 psig. A reduced heat flue gas stream 116then exits the boiler 110 and enters an electrostatic precipitator 117to remove any catalyst fines 118 present in the reduced heat flue gasstream 116 to produce a reduced fines flue gas stream 119. In certainembodiments, the reduced fines flue gas stream 119 has a temperature inthe range of from about 350 to about 800° F.

In certain embodiments, a portion 102 a of the flue gas stream 102 canbe routed through the waste heat steam generator 103, and the resultingreduced fines flue gas stream 109 can be combined with a remainderportion 102 c of the flue gas stream 102 afterwards prior to entering aheat exchanger 120. The heat exchanger 120 is a part of the organicRankine cycle. The heat exchanger 120 may be any type of heat exchangercapable of transferring heat from one fluid stream to another fluidstream. Suitable examples of heat exchangers include, but are notlimited to, heaters, vaporizers, economizers, and other heat recoveryheat exchangers. For example, the heat exchanger 120 may be ashell-and-tube heat exchanger, a plate-fin-tube coil type of exchanger,a bare tube or finned tube bundle, a welded plate heat exchanger, andthe like. Thus, the present invention should not be considered aslimited to any particular type of heat exchanger unless such limitationsare expressly set forth in the appended claims. In certain otherembodiments, the flue gas stream 102 can be entirely routed through thewaste heat steam generator 103. In certain alternative embodiments, aportion 102 b of the flue gas stream 102 can be routed through thethrough the boiler 110, and the resulting reduced fines flue gas stream119 can be combined with the remainder portion 102 c of the flue gasstream 102 afterwards prior to entering the heat exchanger 120. Incertain other embodiments, the flue gas stream 102 can be entirelyrouted through the boiler 110. In yet other embodiments, a first portion102 a of the flue gas stream 102 can be routed through the waste heatsteam generator 103, a second portion 102 b of the flue gas stream 102can be routed through the boiler 110, and the resulting reduced finesflue gas streams 109, 119 can be combined with a third portion 102 c ofthe flue gas stream 102 afterwards prior to entering the heat exchanger120. In certain other embodiments, the flue gas stream 102 can directlyenter heat exchanger 120. One having ordinary skill in the art willrecognize that the flue gas stream 102 can be treated any number of waysand in any combination to produce an input flue gas stream 125 prior toentering the heat exchanger 120.

At least a portion 125 a of the input flue gas stream 125 is thenutilized to heat a working fluid stream 126 in the heat exchanger 120.The portion 125 a of the input flue gas stream 125 thermally contactsthe working fluid stream 126 to transfer heat to the working fluidstream 126. As used herein, the phrase “thermally contact” generallyrefers to the exchange of energy through the process of heat, and doesnot imply physical mixing or direct physical contact of the materials.In certain exemplary embodiments, the working fluid stream 126 includesany working fluid suitable for use in an organic Rankine cycle. Theportion 125 a of the input flue gas stream 125 and the working fluidstream 126 enter the heat exchanger 120 to produce a heated workingfluid stream 128 and a reduced heat flue gas stream 129. In certainexemplary embodiments, the working fluid stream 126 has a temperature inthe range of from about 80 to about 150° F. In certain exemplaryembodiments, the heated working fluid stream 128 has a temperature inthe range of from about 160 to about 450° F. In certain exemplaryembodiments, the heated working fluid stream 128 is vaporized. Incertain exemplary embodiments, the heated working fluid stream 128 isvaporized within a supercritical process, with conditions at atemperature and pressure above the critical point for the heated workingfluid stream 128. In certain exemplary embodiments, the heated workingfluid stream 128 is superheated. In certain exemplary embodiments, theworking fluid stream 126 enters as a high pressure liquid and the heatedworking fluid stream 128 exits as a superheated vapor. In certainexemplary embodiments, the reduced heat flue gas stream 129 has atemperature in the range of from about 300 to about 750° F. In certainembodiments, the reduced heat flue gas stream 129 is cooled to atemperature just above its dew point. The reduced heat flue gas stream129 can then be vented to the atmosphere. In certain exemplaryembodiments, a portion 125 b of the input flue gas stream 125 isdiverted through a bypass valve 130 and then combined with the reducedheat flue gas stream 129 to produce an exhaust flue gas stream 131 to bevented to the atmosphere. In certain exemplary embodiments, the exhaustflue gas stream 131 has a temperature in the range of from about 300° F.to about 800° F. In certain exemplary embodiments, the entire portion125 a of the input flue gas stream 125 is directed through the heatexchanger 120, and is exhausted to the atmosphere at a temperature ofabout 300° F.

At least a portion 128 a of the heated working fluid stream 128 is thendirected to a turbine-generator system 150, which is a part of theorganic Rankine cycle. For purposes of the present application, the term“turbine” will be understood to include both turbines and expanders orany device wherein useful work is generated by expanding a high pressuregas within the device. The portion 128 a of the heated working fluidstream 128 is expanded in the turbine-generator system 150 to produce anexpanded working fluid stream 151 and generate power. In certainexemplary embodiments, the expanded working fluid stream 151 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, the turbine-generator system 150 generates electricity orelectrical power. In certain other embodiments, the turbine-generatorsystem 150 generates mechanical power. In certain embodiments, a portion128 b of the heated working fluid stream 128 is diverted through abypass valve 152 and then combined with the expanded working fluidstream 151 to produce an intermediate working fluid stream 155. Incertain exemplary embodiments, the intermediate working fluid stream 155has a temperature in the range of from about 85 to about 445° F.

The intermediate working fluid stream 155 is then directed to one ormore air-cooled condensers 157. The air-cooled condensers 157 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 157 in series.Suitable examples of air-cooled condensers include, but are not limitedto, air coolers and evaporative coolers. In certain exemplaryembodiments, each of the air-cooled condensers 157 is controlled by avariable frequency drive 158. The air-cooled condensers 157 cool theintermediate working fluid stream 155 to form a condensed working fluidstream 159. In certain exemplary embodiments, the condensed workingfluid stream 159 has a temperature in the range of from about 80 toabout 150° F. The condensed working fluid stream 159 is then directed toa pump 160. The pump 160 is a part of the organic Rankine cycle. Thepump 160 may be any type of commercially available pump sufficient tomeet the pumping requirements of the systems disclosed herein. Incertain exemplary embodiments, the pump 160 is controlled by a variablefrequency drive 161. The pump 160 returns the condensed working fluidstream 159 to a higher pressure to produce the working fluid stream 126that is directed to the heat exchanger 120.

FIG. 2 shows a direct heat recovery system 200 according to anotherexemplary embodiment. The heat recovery system 200 is the same as thatdescribed above with regard to heat recovery system 100, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 2, theintermediate working fluid stream 155 is then directed to one or morewater-cooled condensers 257. The water-cooled condensers 257 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 257 inseries. The water-cooled condensers 257 cool the intermediate workingfluid stream 155 to form a condensed working fluid stream 259. Incertain exemplary embodiments, the condensed working fluid stream 259has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 259 is then directed to the pump 160 andis returned to a higher pressure to produce the working fluid stream 126that is directed to the heat exchanger 120.

FIG. 3 shows an indirect heat recovery system 300 for utilization of aninput flue gas stream 325. The input flue gas stream 325 is the same asthat described above with regard to input flue gas stream 125, and forthe sake of brevity, the similarities will not be repeated hereinbelow.Referring now to FIG. 3, at least a portion 325 a of the input flue gasstream 325 is utilized to heat a working fluid stream 326 in a heatexchanger 320. The portion 325 a of the input flue gas stream 325thermally contacts the working fluid stream 326 and transfers heat tothe working fluid stream 326. Suitable examples of the working fluidstream 326 include, but are not limited to, water, glycols, therminolfluids, alkanes, alkenes, chlorofluorocarbons, hydrofluorocarbons,carbon dioxide (CO2), refrigerants, and mixtures of other hydrocarboncomponents. The portion 325 a of the input flue gas stream 325 and theworking fluid stream 326 enter the heat exchanger 320 to produce aheated working fluid stream 328 and a reduced heat flue gas stream 329.In certain exemplary embodiments, the working fluid stream 326 has atemperature in the range of from about 85 to about 160° F. In certainexemplary embodiments, the heated working fluid stream 328 has atemperature in the range of from about 165 to about 455° F. In certainexemplary embodiments, the reduced heat flue gas stream 329 has atemperature in the range of from about 300 to about 750° F. In certainembodiments, the reduced heat flue gas stream 329 is cooled to atemperature just above its dew point. The reduced heat flue gas stream329 can then be vented to the atmosphere. In certain exemplaryembodiments, a portion 325 b of the input flue gas stream 325 isdiverted through a bypass valve 330 and then combined with the reducedheat flue gas stream 329 to produce an exhaust flue gas stream 331 to bevented to the atmosphere. In certain exemplary embodiments, the exhaustflue gas stream 331 has a temperature in the range of from about 300 toabout 800° F. In certain exemplary embodiments, the input flue gasstream 325 is entirely directed through the heat exchanger 320, and isexhausted to the atmosphere at a temperature of about 300° F.

A portion 328 a of the heated working fluid stream 328 enters a heatexchanger 335 to heat a working fluid stream 336 to produce a heatedworking fluid stream 337 and a reduced heat working fluid stream 338.The portion 328 a of the heated working fluid stream 328 thermallycontacts the working fluid stream 336 and transfers heat to the workingfluid stream 336. In certain exemplary embodiments, the working fluidstream 336 includes any working fluid suitable for use in an organicRankine cycle. In certain exemplary embodiments, the working fluidstream 336 has a temperature in the range of from about 80 to about 150°F. In certain exemplary embodiments, the heated working fluid stream 337has a temperature in the range of from about 160 to about 450° F. Incertain exemplary embodiments, the heated working fluid stream 337 isvaporized. In certain exemplary embodiments, the heated working fluidstream 337 is vaporized within a supercritical process. In certainexemplary embodiments, the heated working fluid stream 337 issuperheated. In certain exemplary embodiments, the reduced heat workingfluid stream 338 has a temperature in the range of from about 85 toabout 155° F. In certain embodiments, a portion 328 b of the heatedworking fluid stream 328 is diverted through a bypass valve 339 and thencombined with the reduced heat working fluid stream 338 to produce anintermediate working fluid stream 340. In certain exemplary embodiments,the intermediate working fluid stream 340 has a temperature in the rangeof from about 85 to about 160° F. The intermediate working fluid stream340 is then directed to a pump 342. In certain exemplary embodiments,the pump 342 is controlled by a variable frequency drive 343. The pump342 returns the intermediate working fluid stream 340 to produce theworking fluid stream 326 that enters the heat exchanger 320.

At least a portion 337 a of the heated working fluid stream 337 is thendirected to a turbine-generator system 350, which is a part of theorganic Rankine cycle. The portion 337 a of the heated working fluidstream 337 is expanded in the turbine-generator system 350 to produce anexpanded working fluid stream 351 and generate power. In certainexemplary embodiments, the expanded working fluid stream 351 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, the turbine-generator system 350 generates electricity orelectrical power. In certain other embodiments, the turbine-generatorsystem 350 generates mechanical power. In certain embodiments, a portion337 b of the heated working fluid stream 337 is diverted through abypass valve 352 and then combined with the expanded working fluidstream 351 to produce an intermediate working fluid stream 355. Incertain exemplary embodiments, the intermediate working fluid stream 355has a temperature in the range of from about 85 to about 445° F.

The intermediate working fluid stream 355 is then directed to one ormore air-cooled condensers 357. The air-cooled condensers 357 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 357 in series.In certain exemplary embodiments, each of the air-cooled condensers 357is controlled by a variable frequency drive 358. The air-cooledcondensers 357 cool the intermediate working fluid stream 355 to form acondensed working fluid stream 359. In certain exemplary embodiments,the condensed working fluid stream 359 has a temperature in the range offrom about 80 to about 150° F. The condensed working fluid stream 359 isthen directed to a pump 360. The pump 360 is a part of the organicRankine cycle. In certain exemplary embodiments, the pump 360 iscontrolled by a variable frequency drive 361. The pump 360 returns thecondensed working fluid stream 359 to a higher pressure to produce theworking fluid stream 336 that is directed to the heat exchanger 335.

FIG. 4 shows an indirect heat recovery system 400 according to anotherexemplary embodiment. The heat recovery system 400 is the same as thatdescribed above with regard to heat recovery system 300, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 4, theintermediate working fluid stream 355 is directed to one or morewater-cooled condensers 457. The water-cooled condensers 457 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 457 inseries. The water-cooled condensers 457 cool the intermediate workingfluid stream 355 to form a condensed working fluid stream 459. Incertain exemplary embodiments, the condensed working fluid stream 459has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 459 is then directed to the pump 360 andis returned to a higher pressure to produce the working fluid stream 336that is directed to the heat exchanger 335.

Referring now to FIG. 5, a direct heat recovery system 500 for utilizingheat from a high temperature reactor, such as a convection section of afired heater 502, is shown. In certain embodiments, the high temperaturereactor is an incinerator, hydrotreater, catalytic reformer, orisomerization unit. Generally, the fired heater 502 is used in arefinery to heat a feedstock stream 503 going to a refinery unit.Suitable examples of refinery units include, but are not limited to,crude distillation units and vacuum distillation units. In certainembodiments, a fuel stream 505 and an air stream 506 enter a burnersection of the fired heater 502 and heat the feedstock stream 503 toproduce a heated feedstock stream 507. In certain embodiments, the heatfrom the resulting flue gas stream 508 can then be used to heat a steamstream 509 to produce a saturated or superheated steam stream 510 and aflue gas stream 511. In certain exemplary embodiments, the flue gasstream 511 has a temperature in the range of from about 350 to about800° F.

The flue gas stream 511 can then be utilized to heat a portion 512 a ofa working fluid stream 512. In certain exemplary embodiments, theworking fluid stream 512 includes any working fluid suitable for use inan organic Rankine cycle. The flue gas stream 511 and the portion 512 aof the working fluid stream 512 enter a heater 513 to produce a heatedworking fluid stream 514 and a reduced heat flue gas stream 515. Theflue gas stream 511 thermally contacts the working fluid stream 512 andtransfers heat to the working fluid stream 512. The heater 513 is a partof the organic Rankine cycle, and can be integrated into the convectionsection of the fired heater 502. In certain exemplary embodiments, theportion 512 a of the working fluid stream 512 has a temperature in therange of from about 80 to about 150° F. In certain exemplaryembodiments, the heated working fluid stream 514 has a temperature inthe range of from about 160 to about 450° F. In certain exemplaryembodiments, the heated working fluid stream 514 is vaporized. Incertain exemplary embodiments, the heated working fluid stream 514 isvaporized within a supercritical process. In certain exemplaryembodiments, the heated working fluid stream 514 is superheated. Incertain exemplary embodiments, the reduced heat flue gas stream 515 hasa temperature in the range of from about 300 to about 750° F. In certainembodiments, the reduced heat flue gas stream 515 has a temperature ofabout 300° F. The reduced heat flue gas stream 515 can then be vented tothe atmosphere. In certain exemplary embodiments, a portion 512 b of theworking fluid stream 512 is diverted through a bypass valve 517 and thencombined with the heated working fluid stream 514 to produce a workingfluid stream 518. In certain exemplary embodiments, the working fluidstream 518 has a temperature in the range of from about 155 to about455° F. In certain exemplary embodiments, the working fluid stream 512is entirely directed through the heater 513.

At least a portion 518 a of the working fluid stream 518 is thendirected to a turbine-generator system 550 where the portion 518 a ofthe working fluid stream 518 is expanded to produce an expanded workingfluid stream 551 and generate power. In certain exemplary embodiments,the expanded working fluid stream 551 has a temperature in the range offrom about 80 to about 440° F. In certain embodiments, theturbine-generator system 550 generates electricity or electrical power.In certain other embodiments, the turbine-generator system 550 generatesmechanical power. In certain embodiments, a portion 518 b of the workingfluid stream 518 is diverted through a bypass valve 552 and thencombined with the expanded working fluid stream 551 to produce anintermediate working fluid stream 555. In certain exemplary embodiments,the intermediate working fluid stream 555 has a temperature in the rangeof from about 85 to about 445° F.

The intermediate working fluid stream 555 is then directed to one ormore air-cooled condensers 557. The air-cooled condensers 557 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 557 in series.In certain exemplary embodiments, each of the air-cooled condensers 557is controlled by a variable frequency drive 558. The air-cooledcondensers 557 cool the intermediate working fluid stream 555 to form acondensed working fluid stream 559. In certain exemplary embodiments,the condensed working fluid stream 559 has a temperature in the range offrom about 80 to about 150° F. The condensed working fluid stream 559 isthen directed to a pump 560. The pump 560 is a part of the organicRankine cycle. In certain exemplary embodiments, the pump 560 iscontrolled by a variable frequency drive 561. The pump 560 returns thecondensed working fluid stream 559 to a higher pressure to produce theworking fluid stream 512 that is directed to the heater 513.

FIG. 6 shows a direct heat recovery system 600 according to anotherexemplary embodiment. The heat recovery system 600 is the same as thatdescribed above with regard to heat recovery system 500, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 6, theintermediate working fluid stream 555 is then directed to one or morewater-cooled condensers 657. The water-cooled condensers 657 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 657 inseries. The water-cooled condensers 657 cool the intermediate workingfluid stream 555 to form a condensed working fluid stream 659. Incertain exemplary embodiments, the condensed working fluid stream 659has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 659 is then directed to the pump 560 andis returned to a higher pressure to produce the working fluid stream 512that is directed to the heater 513.

FIG. 7 shows an indirect heat recovery system 700 for utilization of aflue gas stream 711. The flue gas stream 711 is the same as thatdescribed above with regard to flue gas stream 511, and for the sake ofbrevity, the similarities will not be repeated hereinbelow. Referringnow to FIG. 7, the flue gas stream 711 is utilized to heat a workingfluid stream 712 in a heater 713. The flue gas stream 711 thermallycontacts the working fluid stream 712 and transfers heat to the workingfluid stream 712. Suitable examples of the working fluid stream 712include, but are not limited to, water, glycols, therminol fluids,alkanes, alkenes, chlorofluorocarbons, hydrofluorocarbons, carbondioxide (CO2), refrigerants, and mixtures of other hydrocarboncomponents. The flue gas stream 711 and the portion 712 a of the workingfluid stream 712 enter the heater 713 to produce a heated working fluidstream 714 and a reduced heat flue gas stream 715. The heater 713 can beintegrated into the convection section of a fired heater 702. In certainexemplary embodiments, the portion 712 a of the working fluid stream 712has a temperature in the range of from about 85 to about 160° F. Incertain exemplary embodiments, the heated working fluid stream 714 has atemperature in the range of from about 165 to about 455° F. In certainexemplary embodiments, the reduced heat flue gas stream 715 has atemperature in the range of from about 300 to about 750° F. The reducedheat flue gas stream 715 can then be vented to the atmosphere. Incertain exemplary embodiments, a portion 712 b of the working fluidstream 712 is diverted through a bypass valve 717 and then combined withthe heated working fluid stream 714 to produce a working fluid stream718. In certain exemplary embodiments, the working fluid stream 718 hasa temperature in the range of from about 165 to about 455° F. In certainexemplary embodiments, the working fluid stream 712 is entirely directedthrough the heater 713.

A portion 718 a of the working fluid stream 718 enters a heater 735 toheat a working fluid stream 736 to produce a heated working fluid stream737 and a reduced heat working fluid stream 738. The portion 718 a ofthe working fluid stream 718 thermally contacts the working fluid stream736 and transfers heat to the working fluid stream 736. In certainexemplary embodiments, the working fluid stream 736 includes any workingfluid suitable for use in an organic Rankine cycle. In certain exemplaryembodiments, the working fluid stream 736 has a temperature in the rangeof from about 80 to about 150° F. In certain exemplary embodiments, theheated working fluid stream 737 has a temperature in the range of fromabout 160 to about 450° F. In certain exemplary embodiments, the heatedworking fluid stream 737 is vaporized. In certain exemplary embodiments,the heated working fluid stream 737 is vaporized within a supercriticalprocess. In certain exemplary embodiments, the heated working fluidstream 737 is superheated. In certain exemplary embodiments, the reducedheat working fluid stream 738 has a temperature in the range of fromabout 85 to about 155° F. In certain embodiments, a portion 718 b of theworking fluid stream 718 is diverted through a bypass valve 739 and thencombined with the reduced heat working fluid stream 738 to produce anintermediate working fluid stream 740. In certain exemplary embodiments,the intermediate working fluid stream 740 has a temperature in the rangeof from about 85 to about 160° F. The intermediate working fluid stream740 is directed to a pump 742. In certain exemplary embodiments, thepump 742 is controlled by a variable frequency drive 743. The pump 742returns the intermediate working fluid stream 740 to produce the workingfluid stream 712 that enters the heater 713.

At least a portion 737 a of the heated working fluid stream 737 is thendirected to a turbine-generator system 750, which is a part of theorganic Rankine cycle. The portion 737 a of the heated working fluidstream 737 is expanded in the turbine-generator system 750 to produce anexpanded working fluid stream 751 and generate power. In certainexemplary embodiments, the expanded working fluid stream 751 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, the turbine-generator system 750 generates electricity orelectrical power. In certain other embodiments, the turbine-generatorsystem 750 generates mechanical power. In certain embodiments, a portion737 b of the heated working fluid stream 737 is diverted through abypass valve 752 and then combined with the expanded working fluidstream 751 to produce an intermediate working fluid stream 755. Incertain exemplary embodiments, the intermediate working fluid stream 755has a temperature in the range of from about 80 to about 445° F.

The intermediate working fluid stream 755 is then directed to one ormore air-cooled condensers 757. The air-cooled condensers 757 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 757 in series.In certain exemplary embodiments, each of the air-cooled condensers 757is controlled by a variable frequency drive 758. The air-cooledcondensers 757 cool the intermediate working fluid stream 755 to form acondensed working fluid stream 759. In certain exemplary embodiments,the condensed working fluid stream 759 has a temperature in the range offrom about 80 to about 150° F. The condensed working fluid stream 759 isthen directed to a pump 760. The pump 760 is a part of the organicRankine cycle. In certain exemplary embodiments, the pump 760 iscontrolled by a variable frequency drive 761. The pump 760 returns thecondensed working fluid stream 759 to a higher pressure to produce theworking fluid stream 736 that is directed to the heater 735.

FIG. 8 shows an indirect heat recovery system 800 according to anotherexemplary embodiment. The heat recovery system 800 is the same as thatdescribed above with regard to heat recovery system 700, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 8, theintermediate working fluid stream 755 is directed to one or morewater-cooled condensers 857. The water-cooled condensers 857 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 857 inseries. The water-cooled condensers 857 cool the intermediate workingfluid stream 755 to form a condensed working fluid stream 859. Incertain exemplary embodiments, the condensed working fluid stream 859has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 859 is then directed to the pump 760 andis returned to a higher pressure to produce the working fluid stream 736that is directed to the heater 735.

Referring now to FIG. 9, a direct heat recovery system 900 for utilizinga waste heat by-product stream 901 from a steam generator 902 is shown.Generally, the steam generator 902 is used wherever a source of steam isrequired. In certain embodiments, a fuel stream 905 and an air stream906 enter a burner section 902 a of the steam generator 902 and heat awater stream 903 to produce a steam stream 907 and the waste heatby-product stream 901. In certain exemplary embodiments, the waste heatby-product stream 901 has a temperature in the range of from about 400to about 1000° F.

In certain exemplary embodiments, the waste heat by-product stream 901is directed to a diverter valve 908 and can be separated into an exhauststream 909 and a discharge stream 910. The discharge stream 910 can bedirected to a bypass stack 911 and then discharged to the atmosphere. Aportion 909 a of the exhaust stream 909 can be utilized to heat aworking fluid stream 912. The portion 909 a of the exhaust stream 909thermally contacts the working fluid stream 912 and transfers heat tothe working fluid stream 912. In certain exemplary embodiments, theworking fluid stream 912 includes any working fluid suitable for use inan organic Rankine cycle. The portion 909 a of the exhaust stream 909and the working fluid stream 912 enter a heater 913 to produce a heatedworking fluid stream 914 and a reduced heat exhaust stream 915. Theheater 913 is a part of the organic Rankine cycle. In certain exemplaryembodiments, the working fluid stream 912 has a temperature in the rangeof from about 80 to about 150° F. In certain exemplary embodiments, theheated working fluid stream 914 has a temperature in the range of fromabout 160 to about 450° F. In certain exemplary embodiments, the heatedworking fluid stream 914 is vaporized. In certain exemplary embodiments,the heated working fluid stream 914 is vaporized within a supercriticalprocess. In certain exemplary embodiments, the heated working fluidstream 914 is superheated. In certain exemplary embodiments, the reducedheat exhaust stream 915 has a temperature in the range of from about 300to about 900° F. The reduced heat exhaust stream 915 can then bedirected to a primary stack 916 and discharged to the atmosphere. Incertain exemplary embodiments, the steam generator 902 and the heater913 can be integrated into the primary stack 916. In certain exemplaryembodiments, the reduced heat exhaust stream 915 can be directed to anincinerator or a scrubber prior to being discharged to the atmosphere.In certain exemplary embodiments, a portion 909 b of the exhaust stream909 is diverted through a bypass valve 917 and then combined with thereduced heat exhaust stream 915 to produce an exhaust stream 918. Incertain exemplary embodiments, the exhaust stream 918 has a temperaturein the range of from about 300 to about 905° F. In certain exemplaryembodiments, the exhaust stream 909 is entirely directed through theheater 913.

At least a portion 914 a of the heated working fluid stream 914 is thendirected to a turbine-generator system 950 where the portion 914 a ofthe heated working fluid stream 914 is expanded to produce an expandedworking fluid stream 951 and generate power. In certain exemplaryembodiments, the expanded working fluid stream 951 has a temperature inthe range of from about 80 to about 440° F. In certain embodiments, aportion 914 b of the heated working fluid stream 914 is diverted througha bypass valve 952 and then combined with the expanded working fluidstream 951 to produce an intermediate working fluid stream 955. Incertain exemplary embodiments, the intermediate working fluid stream 955has a temperature in the range of from about 80 to about 445° F.

The intermediate working fluid stream 955 is then directed to one ormore air-cooled condensers 957. The air-cooled condensers 957 are a partof the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 957 in series.In certain exemplary embodiments, each of the air-cooled condensers 957is controlled by a variable frequency drive 958. The air-cooledcondensers 957 cool the intermediate working fluid stream 955 to form acondensed working fluid stream 959. In certain exemplary embodiments,the condensed working fluid stream 959 has a temperature in the range offrom about 80 to about 150° F. The condensed working fluid stream 959 isthen directed to a pump 960. The pump 960 is a part of the organicRankine cycle. In certain exemplary embodiments, the pump 960 iscontrolled by a variable frequency drive 961. The pump 960 returns thecondensed working fluid stream 959 to a higher pressure to produce theworking fluid stream 912 that is directed to the heater 913.

FIG. 10 shows a direct heat recovery system 1000 according to anotherexemplary embodiment. The heat recovery system 1000 is the same as thatdescribed above with regard to heat recovery system 900, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 10, theintermediate working fluid stream 955 is then directed to one or morewater-cooled condensers 1057. The water-cooled condensers 1057 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 1057 inseries. The water-cooled condensers 1057 cool the intermediate workingfluid stream 955 to form a condensed working fluid stream 1059. Incertain exemplary embodiments, the condensed working fluid stream 1059has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 1059 is then directed to the pump 960 andis returned to a higher pressure to produce the working fluid stream 912that is directed to the heater 913.

FIG. 11 shows an indirect heat recovery system 1100 for utilization ofan exhaust stream 1109 from a steam generator 1102. The exhaust stream1109 is the same as that described above with regard to exhaust stream909, and for the sake of brevity, the similarities will not be repeatedhereinbelow. A portion 1109 a of the exhaust stream 1109 can be utilizedto heat a working fluid stream 1112. The portion 1109 a of the exhauststream 1109 thermally contacts the working fluid stream 1112 andtransfers heat to the working fluid stream 1112. Suitable examples ofthe working fluid stream 1112 include, but are not limited to, water,glycols, therminol fluids, alkanes, alkenes, chlorofluorocarbons,hydrofluorocarbons, carbon dioxide (CO2), refrigerants, and mixtures ofother hydrocarbon components. The portion 1109 a of the exhaust stream1109 and the working fluid stream 1112 enter a heater 1113 to produce aheated working fluid stream 1114 and a reduced heat exhaust stream 1115.In certain exemplary embodiments, the working fluid stream 1112 has atemperature in the range of from about 85 to about 160° F. In certainexemplary embodiments, the heated working fluid stream 1114 has atemperature in the range of from about 165 to about 455° F. In certainexemplary embodiments, the reduced heat exhaust stream 1115 has atemperature in the range of from about 300 to about 900° F. The reducedheat exhaust stream 1115 can then be directed to a primary stack 1116and discharged to the atmosphere. In certain exemplary embodiments, thesteam generator 1102 and the heater 1113 can be integrated into theprimary stack 1116. In certain exemplary embodiments, the reduced heatexhaust stream 1115 can be directed to an incinerator or a scrubberprior to being discharged to the atmosphere. In certain exemplaryembodiments, a portion 1109 b of the exhaust stream 1109 is divertedthrough a bypass valve 1117 and then combined with the reduced heatexhaust stream 1115 to produce an exhaust stream 1118. In certainexemplary embodiments, the exhaust stream 1118 has a temperature in therange of from about 300 to about 905° F. In certain exemplaryembodiments, the exhaust stream 1109 is entirely directed through theheater 1113.

At least a portion 1114 a of the heated working fluid stream 1114 entersa heater 1135 to heat a working fluid stream 1136 to produce a heatedworking fluid stream 1137 and a reduced heat working fluid stream 1138.The portion 1114 a of the heated working fluid stream 1114 thermallycontacts the working fluid stream 1136 and transfers heat to the workingfluid stream 1136. In certain exemplary embodiments, the working fluidstream 1136 includes any working fluid suitable for use in an organicRankine cycle. In certain exemplary embodiments, the working fluidstream 1136 has a temperature in the range of from about 80 to about150° F. In certain exemplary embodiments, the heated working fluidstream 1137 has a temperature in the range of from about 160 to about450° F. In certain exemplary embodiments, the heated working fluidstream 1137 is vaporized. In certain exemplary embodiments, the heatedworking fluid stream 1137 is vaporized within a supercritical process.In certain exemplary embodiments, the heated working fluid stream 1137is superheated. In certain exemplary embodiments, the reduced heatworking fluid stream 1138 has a temperature in the range of from about85 to about 155° F. In certain embodiments, a portion 1114 b of theworking fluid stream 1114 is diverted through a bypass valve 1139 andthen combined with the reduced heat working fluid stream 1138 to producean intermediate working fluid stream 1140. In certain exemplaryembodiments, the intermediate working fluid stream 1140 has atemperature in the range of from about 85 to about 160° F. Theintermediate working fluid stream 1140 is directed to a pump 1142. Incertain exemplary embodiments, the pump 1142 is controlled by a variablefrequency drive 1143. The pump 1142 returns the intermediate workingfluid stream 1140 to produce the working fluid stream 1112 that entersthe heater 1113.

At least a portion 1137 a of the heated working fluid stream 1137 isthen directed to a turbine-generator system 1150, which is a part of theorganic Rankine cycle. The portion 1137 a of the heated working fluidstream 1137 is expanded in the turbine-generator system 1150 to producean expanded working fluid stream 1151 and generate power. In certainexemplary embodiments, the expanded working fluid stream 1151 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, the turbine-generator system 1150 generates electricity orelectrical power. In certain other embodiments, the turbine-generatorsystem 1150 generates mechanical power. In certain embodiments, aportion 1137 b of the heated working fluid stream 1137 is divertedthrough a bypass valve 1152 and then combined with the expanded workingfluid stream 1151 to produce an intermediate working fluid stream 1155.In certain exemplary embodiments, the intermediate working fluid stream1155 has a temperature in the range of from about 80 to about 445° F.

The intermediate working fluid stream 1155 is then directed to one ormore air-cooled condensers 1157. The air-cooled condensers 1157 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 1157 in series.In certain exemplary embodiments, each of the air-cooled condensers 1157is controlled by a variable frequency drive 1158. The air-cooledcondensers 1157 cool the intermediate working fluid stream 1155 to forma condensed working fluid stream 1159. In certain exemplary embodiments,the condensed working fluid stream 1159 has a temperature in the rangeof from about 80 to about 150° F. The condensed working fluid stream1159 is then directed to a pump 1160. The pump 1160 is a part of theorganic Rankine cycle. In certain exemplary embodiments, the pump 1160is controlled by a variable frequency drive 1161. The pump 1160 returnsthe condensed working fluid stream 1159 to a higher pressure to producethe working fluid stream 1136 that is directed to the heater 1135.

FIG. 12 shows an indirect heat recovery system 1200 according to anotherexemplary embodiment. The heat recovery system 1200 is the same as thatdescribed above with regard to heat recovery system 1100, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 12, theintermediate working fluid stream 1155 is directed to one or morewater-cooled condensers 1257. The water-cooled condensers 1257 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 1257 inseries. The water-cooled condensers 1257 cool the intermediate workingfluid stream 1155 to form a condensed working fluid stream 1259. Incertain exemplary embodiments, the condensed working fluid stream 1259has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 1259 is then directed to the pump 1160and is returned to a higher pressure to produce the working fluid stream1136 that is directed to the heater 1135.

Referring now to FIG. 13, a direct heat recovery system 1300 forutilizing a waste heat by-product stream 1301 from a gas turbine 1302 isshown. In certain alternative embodiments, the gas turbine is replacedwith a diesel generator (not shown). In certain embodiments, a fuelstream 1305 and an air stream 1306 enter the gas turbine 1302 and iscombusted to produce energy and the waste heat by-product stream 1301.In certain exemplary embodiments, the waste heat by-product stream 1301has a temperature in the range of from about 450 to about 1400° F.

In certain exemplary embodiments, the waste heat by-product stream 1301is directed to a diverter valve 1308 and can be separated into anexhaust stream 1309 and a discharge stream 1310. The discharge stream1310 can be directed to a bypass stack 1311 and then discharged to theatmosphere. A portion 1309 a of the exhaust stream 1309 can be utilizedto heat a working fluid stream 1312. The portion 1309 a of the exhauststream 1309 thermally contacts the working fluid stream 1312 andtransfers heat to the working fluid stream 1312. In certain exemplaryembodiments, the working fluid stream 1312 includes any working fluidsuitable for use in an organic Rankine cycle. The portion 1309 a of theexhaust stream 1309 and the working fluid stream 1312 enter a heater1313 to produce a heated working fluid stream 1314 and a reduced heatexhaust stream 1315. The heater 1313 is a part of the organic Rankinecycle. In certain exemplary embodiments, the working fluid stream 1312has a temperature in the range of from about 80 to about 150° F. Incertain exemplary embodiments, the heated working fluid stream 1314 hasa temperature in the range of from about 160 to about 450° F. In certainexemplary embodiments, the heated working fluid stream 1314 isvaporized. In certain exemplary embodiments, the heated working fluidstream 1314 is vaporized within a supercritical process. In certainexemplary embodiments, the heated working fluid stream 1314 issuperheated. In certain exemplary embodiments, the reduced heat exhauststream 1315 has a temperature in the range of from about 250 to about1000° F. The reduced heat exhaust stream 1315 can then be directed to aprimary stack 1316 and discharged to the atmosphere. In certainexemplary embodiments, the reduced heat exhaust stream 1315 can bedirected to an incinerator or a scrubber prior to being discharged tothe atmosphere. In certain exemplary embodiments, a portion 1309 b ofthe exhaust stream 1309 is diverted through a bypass valve 1317 and thencombined with the reduced heat exhaust stream 1315 to produce an exhauststream 1318. In certain exemplary embodiments, the exhaust stream 1318has a temperature in the range of from about 250 to about 1100° F. Incertain exemplary embodiments, the exhaust stream 1309 is entirelydirected through the heater 1313.

At least a portion 1314 a of the heated working fluid stream 1314 isthen directed to a turbine-generator system 1350 where the portion 1314a of the heated working fluid stream 1314 is expanded to produce anexpanded working fluid stream 1351 and generate power. In certainexemplary embodiments, the expanded working fluid stream 1351 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, a portion 1314 b of the heated working fluid stream 1314 isdiverted through a bypass valve 1352 and then combined with the expandedworking fluid stream 1351 to produce an intermediate working fluidstream 1355. In certain exemplary embodiments, the intermediate workingfluid stream 1355 has a temperature in the range of from about 80 toabout 445° F.

The intermediate working fluid stream 1355 is then directed to one ormore air-cooled condensers 1357. The air-cooled condensers 1357 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 1357 in series.In certain exemplary embodiments, each of the air-cooled condensers 1357is controlled by a variable frequency drive 1358. The air-cooledcondensers 1357 cool the intermediate working fluid stream 1355 to forma condensed working fluid stream 1359. In certain exemplary embodiments,the condensed working fluid stream 1359 has a temperature in the rangeof from about 80 to about 150° F. The condensed working fluid stream1359 is then directed to a pump 1360. The pump 1360 is a part of theorganic Rankine cycle. In certain exemplary embodiments, the pump 1360is controlled by a variable frequency drive 1361. The pump 1360 returnsthe condensed working fluid stream 1359 to a higher pressure to producethe working fluid stream 1312 that is directed to the heater 1313.

FIG. 14 shows a direct heat recovery system 1400 according to anotherexemplary embodiment. The heat recovery system 1400 is the same as thatdescribed above with regard to heat recovery system 1300, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 14, theintermediate working fluid stream 1355 is then directed to one or morewater-cooled condensers 1457. The water-cooled condensers 1457 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 1457 inseries. The water-cooled condensers 1457 cool the intermediate workingfluid stream 1355 to form a condensed working fluid stream 1459. Incertain exemplary embodiments, the condensed working fluid stream 1459has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 1459 is then directed to the pump 1360and is returned to a higher pressure to produce the working fluid stream1312 that is directed to the heater 1313.

FIG. 15 shows an indirect heat recovery system 1500 for utilization ofan exhaust stream 1509. The exhaust stream 1509 is the same as thatdescribed above with regard to exhaust stream 1309, and for the sake ofbrevity, the similarities will not be repeated hereinbelow. A portion1509 a of the exhaust stream 1509 can be utilized to heat a workingfluid stream 1512. The portion 1509 a of the exhaust stream 1509thermally contacts the working fluid stream 1512 and transfers heat tothe working fluid stream 1512. Suitable examples of the working fluidstream 1512 include, but are not limited to, water, glycols, therminolfluids, alkanes, alkenes, chlorofluorocarbons, hydrofluorocarbons,carbon dioxide (CO2), refrigerants, and mixtures of other hydrocarboncomponents. The portion 1509 a of the exhaust stream 1509 and theworking fluid stream 1512 enter a heater 1513 to produce a heatedworking fluid stream 1514 and a reduced heat exhaust stream 1515. Incertain exemplary embodiments, the working fluid stream 1512 has atemperature in the range of from about 85 to about 160° F. In certainexemplary embodiments, the heated working fluid stream 1514 has atemperature in the range of from about 165 to about 455° F. In certainexemplary embodiments, the reduced heat exhaust stream 1515 has atemperature in the range of from about 250 to about 1000° F. The reducedheat exhaust stream 1515 can then be directed to a primary stack 1516and discharged to the atmosphere. In certain exemplary embodiments, thereduced heat exhaust stream 1515 can be directed to an incinerator or ascrubber prior to being discharged to the atmosphere. In certainexemplary embodiments, a portion 1509 b of the exhaust stream 1509 isdiverted through a bypass valve 1517 and then combined with the reducedheat exhaust stream 1515 to produce an exhaust stream 1518. In certainexemplary embodiments, the exhaust stream 1518 has a temperature in therange of from about 250 to about 1100° F. In certain exemplaryembodiments, the exhaust stream 1509 is entirely directed through theheater 1513.

At least a portion 1514 a of the heated working fluid stream 1514 entersa heater 1535 to heat a working fluid stream 1536 to produce a heatedworking fluid stream 1537 and a reduced heat working fluid stream 1538.The portion 1514 a of the heated working fluid stream 1514 thermallycontacts the working fluid stream 1536 and transfers heat to the workingfluid stream 1536. In certain exemplary embodiments, the working fluidstream 1536 includes any working fluid suitable for use in an organicRankine cycle. In certain exemplary embodiments, the working fluidstream 1536 has a temperature in the range of from about 80 to about150° F. In certain exemplary embodiments, the heated working fluidstream 1537 has a temperature in the range of from about 160 to about450° F. In certain exemplary embodiments, the heated working fluidstream 1537 is vaporized. In certain exemplary embodiments, the heatedworking fluid stream 1537 is vaporized within a supercritical process.In certain exemplary embodiments, the heated working fluid stream 1537is superheated. In certain exemplary embodiments, the reduced heatworking fluid stream 1538 has a temperature in the range of from about85 to about 155° F. In certain embodiments, a portion 1514 b of theworking fluid stream 1514 is diverted through a bypass valve 1539 andthen combined with the reduced heat working fluid stream 1538 to producean intermediate working fluid stream 1540. In certain exemplaryembodiments, the intermediate working fluid stream 1540 has atemperature in the range of from about 85 to about 160° F. Theintermediate working fluid stream 1540 is directed to a pump 1542. Incertain exemplary embodiments, the pump 1542 is controlled by a variablefrequency drive 1543. The pump 1542 returns the intermediate workingfluid stream 1540 to produce the working fluid stream 1512 that entersthe heater 1513.

At least a portion 1537 a of the heated working fluid stream 1537 isthen directed to a turbine-generator system 1550, which is a part of theorganic Rankine cycle. The portion 1537 a of the heated working fluidstream 1537 is expanded in the turbine-generator system 1550 to producean expanded working fluid stream 1551 and generate power. In certainexemplary embodiments, the expanded working fluid stream 1551 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, the turbine-generator system 1550 generates electricity orelectrical power. In certain other embodiments, the turbine-generatorsystem 1550 generates mechanical power. In certain embodiments, aportion 1537 b of the heated working fluid stream 1537 is divertedthrough a bypass valve 1552 and then combined with the expanded workingfluid stream 1551 to produce an intermediate working fluid stream 1555.In certain exemplary embodiments, the intermediate working fluid stream1555 has a temperature in the range of from about 80 to about 445° F.

The intermediate working fluid stream 1555 is then directed to one ormore air-cooled condensers 1557. The air-cooled condensers 1557 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 1557 in series.In certain exemplary embodiments, each of the air-cooled condensers 1557is controlled by a variable frequency drive 1558. The air-cooledcondensers 1557 cool the intermediate working fluid stream 1555 to forma condensed working fluid stream 1559. In certain exemplary embodiments,the condensed working fluid stream 1559 has a temperature in the rangeof from about 80 to about 150° F. The condensed working fluid stream1559 is then directed to a pump 1560. The pump 1560 is a part of theorganic Rankine cycle. In certain exemplary embodiments, the pump 1560is controlled by a variable frequency drive 1561. The pump 1560 returnsthe condensed working fluid stream 1559 to a higher pressure to producethe working fluid stream 1536 that is directed to the heater 1535.

FIG. 16 shows an indirect heat recovery system 1600 according to anotherexemplary embodiment. The heat recovery system 1600 is the same as thatdescribed above with regard to heat recovery system 1500, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 16, theintermediate working fluid stream 1555 is directed to one or morewater-cooled condensers 1657. The water-cooled condensers 1657 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 1657 inseries. The water-cooled condensers 1657 cool the intermediate workingfluid stream 1555 to form a condensed working fluid stream 1659. Incertain exemplary embodiments, the condensed working fluid stream 1659has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 1659 is then directed to the pump 1560and is returned to a higher pressure to produce the working fluid stream1536 that is directed to the heater 1535.

Referring now to FIG. 17, a direct heat recovery system 1700 forutilizing a heat by-product stream 1701 from a process column 1702 isshown. Suitable examples of process columns include, but are not limitedto, distillation columns and strippers. In certain exemplaryembodiments, the heat by-product stream 1701 has a temperature in therange of from about 170 to about 700° F. A portion 1701 a of the heatby-product stream 1701 can be utilized to heat a working fluid stream1712. The portion 1701 a of the heat by-product stream 1701 thermallycontacts the working fluid stream 1712 and transfers heat to the workingfluid stream 1712. In certain exemplary embodiments, the working fluidstream 1712 includes any working fluid suitable for use in an organicRankine cycle. The portion 1701 a of the heat by-product stream 1701 andthe working fluid stream 1712 enter a heater 1713 to produce a heatedworking fluid stream 1714 and a reduced heat exhaust stream 1715. Theheater 1713 is a part of the organic Rankine cycle. In certain exemplaryembodiments, the working fluid stream 1712 has a temperature in therange of from about 80 to about 150° F. In certain exemplaryembodiments, the heated working fluid stream 1714 has a temperature inthe range of from about 160 to about 450° F. In certain exemplaryembodiments, the heated working fluid stream 1714 is vaporized. Incertain exemplary embodiments, the heated working fluid stream 1714 isvaporized within a supercritical process. In certain exemplaryembodiments, the heated working fluid stream 1714 is superheated. Incertain exemplary embodiments, the reduced heat exhaust stream 1715 hasa temperature in the range of from about 90 to about 500° F. The reducedheat exhaust stream 1715 can then be vented to the atmosphere. Incertain exemplary embodiments, a portion 1701 b of the heat by-productstream 1701 is diverted through a bypass valve 1717 and then combinedwith the reduced heat exhaust stream 1715 to produce an exhaust stream1718. In certain exemplary embodiments, the exhaust stream 1718 has atemperature in the range of from about 90 to about 510° F. In certainexemplary embodiments, the heat by-product stream 1701 is entirelydirected through the heater 1713.

At least a portion 1714 a of the heated working fluid stream 1714 isthen directed to a turbine-generator system 1750 where the portion 1714a of the heated working fluid stream 1714 is expanded to produce anexpanded working fluid stream 1751 and generate power. In certainexemplary embodiments, the expanded working fluid stream 1751 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, a portion 1714 b of the heated working fluid stream 1714 isdiverted through a bypass valve 1752 and then combined with the expandedworking fluid stream 1751 to produce an intermediate working fluidstream 1755. In certain exemplary embodiments, the intermediate workingfluid stream 1755 has a temperature in the range of from about 80 toabout 455° F.

The intermediate working fluid stream 1755 is then directed to one ormore air-cooled condensers 1757. The air-cooled condensers 1757 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 1757 in series.In certain exemplary embodiments, each of the air-cooled condensers 1757is controlled by a variable frequency drive 1758. The air-cooledcondensers 1757 cool the intermediate working fluid stream 1755 to forma condensed working fluid stream 1759. In certain exemplary embodiments,the condensed working fluid stream 1759 has a temperature in the rangeof from about 80 to about 150° F. The condensed working fluid stream1759 is then directed to a pump 1760. The pump 1760 is a part of theorganic Rankine cycle. In certain exemplary embodiments, the pump 1760is controlled by a variable frequency drive 1761. The pump 1760 returnsthe condensed working fluid stream 1759 to a higher pressure to producethe working fluid stream 1712 that is directed to the heater 1713.

FIG. 18 shows a direct heat recovery system 1800 according to anotherexemplary embodiment. The heat recovery system 1800 is the same as thatdescribed above with regard to heat recovery system 1700, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 18, theintermediate working fluid stream 1755 is then directed to one or morewater-cooled condensers 1857. The water-cooled condensers 1857 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 1857 inseries. The water-cooled condensers 1857 cool the intermediate workingfluid stream 1755 to form a condensed working fluid stream 1859. Incertain exemplary embodiments, the condensed working fluid stream 1859has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 1859 is then directed to the pump 1760and is returned to a higher pressure to produce the working fluid stream1712 that is directed to the heater 1713.

FIG. 19 shows an indirect heat recovery system 1900 for utilization ofheat by-product stream 1901. The heat by-product stream 1901 is the sameas that described above with regard to heat by-product stream 1701, andfor the sake of brevity, the similarities will not be repeatedhereinbelow. A portion 1901 a of the heat by-product stream 1901 can beutilized to heat a working fluid stream 1912. The portion 1901 a of theheat by-product stream 1901 thermally contacts the working fluid stream1912 and transfers heat to the working fluid stream 1912. Suitableexamples of the working fluid stream 1912 include, but are not limitedto, water, glycols, therminol fluids, alkanes, alkenes,chlorofluorocarbons, hydrofluorocarbons, carbon dioxide (CO2),refrigerants, and mixtures of other hydrocarbon components. The portion1901 a of the heat by-product stream 1901 and the working fluid stream1912 enter a heater 1913 to produce a heated working fluid stream 1914and a reduced heat exhaust stream 1915. In certain exemplaryembodiments, the working fluid stream 1912 has a temperature in therange of from about 85 to about 160° F. In certain exemplaryembodiments, the heated working fluid stream 1914 has a temperature inthe range of from about 165 to about 455° F. In certain exemplaryembodiments, the reduced heat exhaust stream 1915 has a temperature inthe range of from about 90 to about 500° F. The reduced heat exhauststream 1915 can then be vented to the atmosphere. In certain exemplaryembodiments, a portion 1901 b of the heat by-product stream 1901 isdiverted through a bypass valve 1917 and then combined with the reducedheat exhaust stream 1915 to produce an exhaust stream 1918. In certainexemplary embodiments, the exhaust stream 1918 has a temperature in therange of from about 90 to about 510° F. In certain exemplaryembodiments, the heat by-product stream 1901 is entirely directedthrough the heater 1913.

At least a portion 1914 a of the heated working fluid stream 1914 entersa heater 1935 to heat a working fluid stream 1936 to produce a heatedworking fluid stream 1937 and a reduced heat working fluid stream 1938.The portion 1914 a of the heated working fluid stream 1914 thermallycontacts the working fluid stream 1936 and transfers heat to the workingfluid stream 1936. In certain exemplary embodiments, the working fluidstream 1936 includes any working fluid suitable for use in an organicRankine cycle. In certain exemplary embodiments, the working fluidstream 1936 has a temperature in the range of from about 80 to about150° F. In certain exemplary embodiments, the heated working fluidstream 1937 has a temperature in the range of from about 160 to about450° F. In certain exemplary embodiments, the heated working fluidstream 1937 is vaporized. In certain exemplary embodiments, the heatedworking fluid stream 1937 is vaporized within a supercritical process.In certain exemplary embodiments, the heated working fluid stream 1937is superheated. In certain exemplary embodiments, the reduced heatworking fluid stream 1938 has a temperature in the range of from about85 to about 155° F. In certain embodiments, a portion 1914 b of theworking fluid stream 1914 is diverted through a bypass valve 1939 andthen combined with the reduced heat working fluid stream 1938 to producean intermediate working fluid stream 1940. In certain exemplaryembodiments, the intermediate working fluid stream 1940 has atemperature in the range of from about 85 to about 160° F. Theintermediate working fluid stream 1940 is directed to a pump 1942. Incertain exemplary embodiments, the pump 1942 is controlled by a variablefrequency drive 1943. The pump 1942 returns the intermediate workingfluid stream 1940 to produce the working fluid stream 1912 that entersthe heater 1913.

At least a portion 1937 a of the heated working fluid stream 1937 isthen directed to a turbine-generator system 1950, which is a part of theorganic Rankine cycle. The portion 1937 a of the heated working fluidstream 1937 is expanded in the turbine-generator system 1950 to producean expanded working fluid stream 1951 and generate power. In certainexemplary embodiments, the expanded working fluid stream 1951 has atemperature in the range of from about 80 to about 440° F. In certainembodiments, the turbine-generator system 1950 generates electricity orelectrical power. In certain other embodiments, the turbine-generatorsystem 1950 generates mechanical power. In certain embodiments, aportion 1937 b of the heated working fluid stream 1937 is divertedthrough a bypass valve 1952 and then combined with the expanded workingfluid stream 1951 to produce an intermediate working fluid stream 1955.In certain exemplary embodiments, the intermediate working fluid stream1955 has a temperature in the range of from about 80 to about 445° F.

The intermediate working fluid stream 1955 is then directed to one ormore air-cooled condensers 1957. The air-cooled condensers 1957 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two air-cooled condensers 1957 in series.In certain exemplary embodiments, each of the air-cooled condensers 1957is controlled by a variable frequency drive 1958. The air-cooledcondensers 1957 cool the intermediate working fluid stream 1955 to forma condensed working fluid stream 1959. In certain exemplary embodiments,the condensed working fluid stream 1959 has a temperature in the rangeof from about 80 to about 150° F. The condensed working fluid stream1959 is then directed to a pump 1960. The pump 1960 is a part of theorganic Rankine cycle. In certain exemplary embodiments, the pump 1960is controlled by a variable frequency drive 1961. The pump 1960 returnsthe condensed working fluid stream 1959 to a higher pressure to producethe working fluid stream 1936 that is directed to the heater 1935.

FIG. 20 shows an indirect heat recovery system 2000 according to anotherexemplary embodiment. The heat recovery system 2000 is the same as thatdescribed above with regard to heat recovery system 1900, except asspecifically stated below. For the sake of brevity, the similaritieswill not be repeated hereinbelow. Referring now to FIG. 20, theintermediate working fluid stream 1955 is directed to one or morewater-cooled condensers 2057. The water-cooled condensers 2057 are apart of the organic Rankine cycle. In certain exemplary embodiments, theorganic Rankine cycle includes two water-cooled condensers 2057 inseries. The water-cooled condensers 2057 cool the intermediate workingfluid stream 1955 to form a condensed working fluid stream 2059. Incertain exemplary embodiments, the condensed working fluid stream 2059has a temperature in the range of from about 80 to about 150° F. Thecondensed working fluid stream 2059 is then directed to the pump 1960and is returned to a higher pressure to produce the working fluid stream1936 that is directed to the heater 1935.

The present invention may employ any number of working fluids in theorganic Rankine cycle. Suitable examples of working fluids for use inthe organic Rankine cycle include, but are not limited to, ammonia(NH3), bromine (Br2), carbon tetrachloride (CCl4), ethyl alcohol orethanol (CH3CH2OH, C2H60), furan (C4H40), hexafluorobenzene orperfluoro-benzene (C6F6), hydrazine (N2H4), methyl alcohol or methanol(CH3OH), monochlorobenzene or chlorobenzene or chlorobenzol or benzinechloride (C6H5Cl), n-pentane or normal pentane (nC5), i-hexane orisohexane (iC5), pyridene or azabenzene (C5H5N), refrigerant 11 or freon11 or CFC-11 or R-11 or trichlorofluoromethane (CCl3F), refrigerant 12or freon 12 or R-12 or dichlorodifluoromethane (CCl2F2), refrigerant 21or freon 21 or CFC-21 or R-21 (CHCl2F), refrigerant 30 or freon 30 orCFC-30 or R-30 or dichloromethane or methylene chloride or methylenedichloride (CH2Cl2), refrigerant 115 or freon 115 or CFC-115 or R-115 orchloro-pentafluoroethane or monochloropentafluoroethane, refrigerant 123or freon 123 or HCFC-123 or R-123 or 2,2 dichloro-1,1,1-trifluoroethane,refrigerant 123a or freon 123a or HCFC-123a or R-123a or1,2-dichloro-1,1,2-trifluoroethane, refrigerant 123b1 or freon 123b1 orHCFC-123b1 or R-123b1 or halothane or2-bromo-2-chloro-1,1,1-trifluoroethane, refrigerant 134A or freon 134Aor HFC-134A or R-134A or 1,1,1,2-tetrafluoroethane, refrigerant 150A orfreon 150A or CFC-150A or R-150A or dichloroethane or ethylenedichloride (CH3CHCl2), thiophene (C4H4S), toluene or methylbenzene orphenylmethane or toluol (C7H8), water (H2O), carbon dioxide (CO2), andthe like. In certain exemplary embodiments, the working fluid mayinclude a combination of components. For example, one or more of thecompounds identified above may be combined or with a hydrocarbon fluid,for example, isobutene. However, those skilled in the art will recognizethat the present invention is not limited to any particular type ofworking fluid or refrigerant. Thus, the present invention should not beconsidered as limited to any particular working fluid unless suchlimitations are clearly set forth in the appended claims.

The present application is generally directed to various heat recoverysystems and methods for producing electrical and/or mechanical powerfrom a heat source. The exemplary systems may include a heat exchanger,a turbine-generator set, a condenser heat exchanger, and a pump. Thepresent invention is advantageous over conventional heat recoverysystems and methods as it utilizes heat that would otherwise be rejectedto the atmosphere to produce electricity and/or mechanical power, thusincreasing process efficiency

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. While numerous changes may be made bythose skilled in the art, such changes are encompassed within the spiritof this invention as defined by the appended claims. Furthermore, nolimitations are intended to the details of construction or design hereinshown, other than as described in the claims below. It is thereforeevident that the particular illustrative embodiments disclosed above maybe altered or modified and all such variations are considered within thescope and spirit of the present invention. The terms in the claims havetheir plain, ordinary meaning unless otherwise explicitly and clearlydefined by the patentee.

1. A process for utilizing process heat by-product from refineryoperations, comprising: a first sub-process and a second sub-process,the first sub-process comprising the steps of: a) directing process heatby-product from a refinery operation to a heater; b) thermallycontacting in said heater the process heat by-product with a workingfluid to cool the process heat by-product to form a cooled by-product;c) exhausting the cooled by-product to atmosphere; and the secondsub-process comprising the steps of: d) heating in said heater theworking fluid to form a heated working fluid; e) passing the heatedworking fluid through a turbine to form an expanded working fluid,wherein said passing of the heated working fluid through the turbinedrives a generator for production of one of electricity and mechanicalpower; f) passing the expanded working fluid through at least one heatexchanger to form a condensed working fluid; and g) passing thecondensed working fluid through at least one pump to form said workingfluid; wherein the first and second sub-processes are linked via theheater, and wherein first and second sub-processes occur simultaneously.2. The process of claim 1, wherein the at least one heat exchanger isselected from the group consisting of air-cooled condensers andwater-cooled condensers.
 3. The process of claim 1, wherein said processheat by-product comprises flue gas or waste heat from refineryoperations.
 4. The process of claim 1, wherein said process heatby-product comprises flue gas from a fluid catalytic cracking unit. 5.The process of claim 1, wherein said process heat by-product comprisesheat by-product generated by directing flue gas from a fluid catalyticcracking regenerator to a waste heat steam generator for generatingsteam, passing said flue gas through an electrostatic precipitator toremove catalyst fines present in the flue gas, and recovering theprocess heat by-product from the flue gas exiting the electrostaticprecipitator.
 6. The process of claim 1, wherein said process heatby-product comprises heat by-product generated by directing a flue gasfrom a fluid catalytic cracking regenerator to a boiler, wherein theflue gas comprises carbon monoxide, combusting the carbon monoxide inthe boiler to generate steam, passing the flue gas through anelectrostatic precipitator to remove catalyst fines present in the fluegas, and recovering the process heat by-product from the flue gasexiting the electrostatic precipitator.
 7. The process of claim 1,wherein said process heat by-product comprises recovered heat from ahigh temperature reactor.
 8. The process of claim 7, wherein the hightemperature reactor is a fired heater or an incinerator.
 9. The processof claim 7, wherein said heater is integral to a convection section ofthe high temperature reactor.
 10. The process of claim 1, wherein theworking fluid is selected from the group consisting of organic workingfluids and refrigerants.
 11. The process of claim 1, wherein the step ofheating the working fluid to form the heated working fluid comprisesvaporizing the working fluid.
 12. The process of claim 1, wherein thestep of heating the working fluid to form the heated working fluidcomprises vaporizing the working fluid within a supercritical process.13. A process for utilizing waste heat by-product, comprising: a firstsub-process and a second sub-process, the first sub-process comprisingthe steps of: a) directing waste heat by-product to a heater; b)thermally contacting in said heater the waste heat by-product with aworking fluid to cool the waste heat by-product to form a cooledby-product; c) exhausting the cooled by-product to atmosphere; and thesecond sub-process comprising the steps of: d) heating in said heaterthe working fluid to form a heated working fluid; e) passing the heatedworking fluid through a turbine to form an expanded working fluid,wherein said passing of the heated working fluid through the turbinedrives a generator for production of one of electricity and mechanicalpower; f) passing the expanded working fluid through at least one heatexchanger to form a condensed working fluid; and g) passing thecondensed working fluid through at least one pump to form said workingfluid; wherein the first and second sub-processes are linked via theheater, and wherein first and second sub-processes occur simultaneously.14. The process of claim 13, wherein the at least one heat exchanger isselected from the group consisting of air-cooled condensers andwater-cooled condensers.
 15. The process of claim 13, further comprisingthe step of directing the cooled by-product to one of an incinerator, ascrubber, and a stack prior to exhausting the cooled by-product to theatmosphere.
 16. The process of claim 13, wherein said waste heatby-product comprises waste heat from a steam generator.
 17. The processof claim 13, wherein said waste heat by-product is generated bydirecting water into a steam generator, heating the water with a heatedair stream to form steam and the waste heat by-product.
 18. The processof claim 17, further comprising the step of diverting a portion of thewaste heat by-product through a diverter valve for discharging toatmosphere.
 19. The process of claim 13, wherein said waste heatby-product comprises waste heat from a gas turbine.
 20. The process ofclaim 13, wherein said waste heat by-product is generated by directingfuel into a gas turbine, and combusting the fuel in the gas turbine togenerate power and the waste heat by-product.
 21. The process of claim13, wherein the working fluid is selected from the group consisting oforganic working fluids and refrigerants.
 22. The process of claim 13,wherein the step of heating the working fluid to form the heated workingfluid comprises vaporizing the working fluid.
 23. The process of claim13, wherein the step of heating the working fluid to form the heatedworking fluid comprises vaporizing the working fluid within asupercritical process.
 24. A process for utilizing a heat by-product,comprising: a first sub-process and a second sub-process, the firstsub-process comprising the steps of: a) directing the heat by-product toa heater; b) thermally contacting in said heater the heat by-productwith a working fluid to cool the heat by-product to form a cooledby-product; c) exhausting the cooled by-product to atmosphere; and thesecond sub-process comprising the steps of: d) heating in said heaterthe working fluid to form a heated working fluid; e) passing the heatedworking fluid through a turbine to form an expanded working fluid,wherein said passing of the heated working fluid through the turbinepowers a generator for production of one of electricity and mechanicalpower; f) passing the expanded working fluid through at least one heatexchanger to form a condensed working fluid; and g) passing thecondensed working fluid through at least one pump to form said workingfluid; wherein the first and second sub-processes are linked via theheater, and wherein first and second sub-processes occur simultaneously.